When you think of romance, you probably don't think of insects. But for one species of beetle, love is in the air every other night. The large black chafer beetle, Holotrichia parallela, has a unique 48-hour cycle that regulates its mating behavior and sense of smell. This unusual rhythm makes this beetle a fascinating subject for biologists, but also a major threat for farmers.
This knowledge could be used to disrupt the beetle's chemical communication, lure and capture the males, or target them during their active phases.
By studying this beetle, we could not only protect our crops, but also learn more about the diversity and adaptability of life on Earth.
The 48-Hour Mystery of the Large Black Chafer Beetle
Paulo Ziemer/Unsplash
Imagine having a date night only once every two days. That's the reality for the large black chafer beetle, an insect that lives in Asia. Unlike most living beings that follow a 24-hour cycle, this beetle has a rare 48-hour rhythm, called "circa-bi-dian".
Every other night, female beetles crawl out of the soil and climb up a plant to release a seductive scent, called LIME, that attracts males. This mating behavior is controlled by a 48-hour clock, but the reason for this unusual pattern is still unknown.
Scientists have recently discovered that the male beetles' ability to smell the females is also on a 48-hour cycle. They identified a gene, HparOR14, that acts as the sex pheromone receptor in the beetles' antennae.
They found that this gene is more active on the nights when females are releasing LIME, but less active on the other nights.
This means that the male beetles are synchronized with the females' mating schedule, but how they achieve this is a mystery. There are no environmental cues, such as light or temperature, that follow a 48-hour cycle in nature.
How do these beetles set and maintain their unique biological clocks?
The large black chafer beetle is not just a curiosity for biologists. It is also a serious agricultural pest that causes damage to crops such as rice, corn, and sugarcane. The larvae feed on the roots of the plants, while the adults feed on the leaves and stems.
Understanding the beetle's 48-hour cycle could help farmers and researchers develop better pest control strategies. For example, they could target the beetles during their active phases, when they are more likely to be exposed to insecticides or traps.
They could also use synthetic LIME to lure and capture the males, or disrupt their chemical communication.
The study of the beetle's 48-hour cycle could also shed light on the complex mechanisms of biological timekeeping in general. How did such a unique rhythm evolve and what are its advantages and disadvantages?
How does it affect the beetle's metabolism and behavior? How common are 48-hour cycles in other organisms?
These are some of the questions that the researchers hope to answer in the future. By studying this beetle, they could uncover new insights into the diversity and adaptability of life on Earth.
